diff --git a/src/nvmath/SphericalHarmonic.cpp b/src/nvmath/SphericalHarmonic.cpp
index 25832e7..d0d4423 100644
--- a/src/nvmath/SphericalHarmonic.cpp
+++ b/src/nvmath/SphericalHarmonic.cpp
@@ -1,6 +1,8 @@
 // This code is in the public domain -- castanyo@yahoo.es
 
-#include <nvmath/SphericalHarmonic.h>
+#include "SphericalHarmonic.h"
+
+#include "Vector.h"
 
 using namespace nv;
 
diff --git a/src/nvmath/SphericalHarmonic.h b/src/nvmath/SphericalHarmonic.h
index 3847d57..b7f5774 100644
--- a/src/nvmath/SphericalHarmonic.h
+++ b/src/nvmath/SphericalHarmonic.h
@@ -3,20 +3,21 @@
 #ifndef NV_MATH_SPHERICALHARMONIC_H
 #define NV_MATH_SPHERICALHARMONIC_H
 
-#include "Vector.h"
+#include "nvmath.h"
 
 #include <string.h> // memcpy
 
 
 namespace nv
 {
+    class Vector3;
     class Matrix;
 
     NVMATH_API float legendrePolynomial( int l, int m, float x ) NV_CONST;
     NVMATH_API float shBasis( int l, int m, float theta, float phi ) NV_CONST;
-    NVMATH_API float shBasis( int l, int m, Vector3::Arg v ) NV_CONST;
+    NVMATH_API float shBasis( int l, int m, const Vector3 & v ) NV_CONST;
     NVMATH_API float hshBasis( int l, int m, float theta, float phi ) NV_CONST;
-    NVMATH_API float hshBasis( int l, int m, Vector3::Arg v ) NV_CONST;
+    NVMATH_API float hshBasis( int l, int m, const Vector3 & v ) NV_CONST;
 
     class Sh;
     float dot(const Sh & a, const Sh & b) NV_CONST;
@@ -185,7 +186,7 @@ namespace nv
         }*/
 
         /// Evaluate 
-        void eval(Vector3::Arg dir)
+        void eval(const Vector3 & dir)
         {
             for(int l = 0; l <= m_order; l++) {
                 for(int m = -l; m <= l; m++) {
@@ -196,7 +197,7 @@ namespace nv
 
 
         /// Evaluate the spherical harmonic function.
-        float sample(Vector3::Arg dir) const
+        float sample(const Vector3 & dir) const
         {
             Sh sh(order());
             sh.eval(dir);